<template>
  <div class="card filter">
    <h4 v-if="title" class="title sle">
      {{ title }}
    </h4>
    <el-input v-model="filterText" placeholder="输入关键字进行过滤" clearable />
    <el-scrollbar :style="{ height: title ? `calc(100% - 95px)` : `calc(100% - 56px)` }">
      <el-tree
        ref="treeRef"
        default-expand-all
        :node-key="id"
        :data="multiple ? treeData : treeAllData"
        :show-checkbox="multiple"
        :check-strictly="false"
        :current-node-key="!multiple ? selected : ''"
        :highlight-current="!multiple"
        :expand-on-click-node="false"
        :check-on-click-node="multiple"
        :props="defaultProps"
        :filter-node-method="filterNode"
        :default-checked-keys="multiple ? selected : []"
        @node-click="handleNodeClick"
        @check="handleCheckChange"
      >
        <template #default="scope">
          <span class="el-tree-node__label">
            <slot :row="scope">
              {{ scope.node.label }}
            </slot>
          </span>
        </template>
      </el-tree>
    </el-scrollbar>
  </div>
</template>

<script setup lang="ts" name="TreeFilter">
  import { ref, watch, onBeforeMount, nextTick } from "vue"
  import { ElTree } from "element-plus"

  // 接收父组件参数并设置默认值
  interface TreeFilterProps {
    requestApi?: (data?: any) => Promise<any> // 请求分类数据的 api ==> 非必传
    data?: { [key: string]: any }[] // 分类数据，如果有分类数据，则不会执行 api 请求 ==> 非必传
    title?: string // treeFilter 标题 ==> 非必传
    id?: string // 选择的id ==> 非必传，默认为 “id”
    label?: string // 显示的label ==> 非必传，默认为 “label”
    multiple?: boolean // 是否为多选 ==> 非必传，默认为 false
    defaultValue?: any // 默认选中的值 ==> 非必传
  }
  const props = withDefaults(defineProps<TreeFilterProps>(), {
    id: "id",
    label: "label",
    multiple: false
  })

  const defaultProps = {
    children: "children",
    label: props.label
  }

  const treeRef = ref<InstanceType<typeof ElTree>>()
  const treeData = ref<{ [key: string]: any }[]>([])
  const treeAllData = ref<{ [key: string]: any }[]>([])

  const selected = ref()
  const setSelected = () => {
    if (props.multiple) selected.value = Array.isArray(props.defaultValue) ? props.defaultValue : [props.defaultValue]
    else selected.value = typeof props.defaultValue === "string" ? props.defaultValue : ""
  }

  onBeforeMount(async () => {
    setSelected()
    if (props.requestApi) {
      const { data } = await props.requestApi!()
      treeData.value = data
      treeAllData.value = [{ id: "", [props.label]: "全部" }, ...data]
    }
  })

  // 使用 nextTick 防止打包后赋值不生效，开发环境是正常的
  watch(
    () => props.defaultValue,
    () => nextTick(() => setSelected()),
    { deep: true, immediate: true }
  )

  watch(
    () => props.data,
    () => {
      if (props.data?.length) {
        treeData.value = props.data
        treeAllData.value = [{ id: "", [props.label]: "全部" }, ...props.data]
      }
    },
    { deep: true, immediate: true }
  )

  const filterText = ref("")
  watch(filterText, (val) => {
    treeRef.value!.filter(val)
  })

  // 过滤
  const filterNode = (value: string, data: { [key: string]: any }, node: any) => {
    if (!value) return true
    let parentNode = node.parent,
      labels = [node.label],
      level = 1
    while (level < node.level) {
      labels = [...labels, parentNode.label]
      parentNode = parentNode.parent
      level++
    }
    return labels.some((label) => label.indexOf(value) !== -1)
  }

  interface FilterEmits {
    (e: "change", value: any): void
  }
  const emit = defineEmits<FilterEmits>()

  // 单选
  const handleNodeClick = (data: { [key: string]: any }) => {
    if (props.multiple) return
    emit("change", data[props.id])
  }

  // 多选
  const handleCheckChange = () => {
    emit("change", treeRef.value?.getCheckedKeys())
  }

  // 暴露给父组件使用
  defineExpose({ treeData, treeAllData, treeRef })
</script>

<style scoped lang="scss">
  @import "./index.scss";
</style>
